deps/v8/src/arm/constants-arm.h
// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_ARM_CONSTANTS_ARM_H_
#define V8_ARM_CONSTANTS_ARM_H_
// ARM EABI is required.
#if defined(__arm__) && !defined(__ARM_EABI__)
#error ARM EABI support is required.
#endif
namespace v8 {
namespace internal {
// Constant pool marker.
// Use UDF, the permanently undefined instruction.
const int kConstantPoolMarkerMask = 0xfff000f0;
const int kConstantPoolMarker = 0xe7f000f0;
const int kConstantPoolLengthMaxMask = 0xffff;
inline int EncodeConstantPoolLength(int length) {
DCHECK((length & kConstantPoolLengthMaxMask) == length);
return ((length & 0xfff0) << 4) | (length & 0xf);
}
inline int DecodeConstantPoolLength(int instr) {
DCHECK((instr & kConstantPoolMarkerMask) == kConstantPoolMarker);
return ((instr >> 4) & 0xfff0) | (instr & 0xf);
}
// Used in code age prologue - ldr(pc, MemOperand(pc, -4))
const int kCodeAgeJumpInstruction = 0xe51ff004;
// Number of registers in normal ARM mode.
const int kNumRegisters = 16;
// VFP support.
const int kNumVFPSingleRegisters = 32;
const int kNumVFPDoubleRegisters = 32;
const int kNumVFPRegisters = kNumVFPSingleRegisters + kNumVFPDoubleRegisters;
// PC is register 15.
const int kPCRegister = 15;
const int kNoRegister = -1;
// -----------------------------------------------------------------------------
// Conditions.
// Defines constants and accessor classes to assemble, disassemble and
// simulate ARM instructions.
//
// Section references in the code refer to the "ARM Architecture Reference
// Manual" from July 2005 (available at http://www.arm.com/miscPDFs/14128.pdf)
//
// Constants for specific fields are defined in their respective named enums.
// General constants are in an anonymous enum in class Instr.
// Values for the condition field as defined in section A3.2
enum Condition {
kNoCondition = -1,
eq = 0 << 28, // Z set Equal.
ne = 1 << 28, // Z clear Not equal.
cs = 2 << 28, // C set Unsigned higher or same.
cc = 3 << 28, // C clear Unsigned lower.
mi = 4 << 28, // N set Negative.
pl = 5 << 28, // N clear Positive or zero.
vs = 6 << 28, // V set Overflow.
vc = 7 << 28, // V clear No overflow.
hi = 8 << 28, // C set, Z clear Unsigned higher.
ls = 9 << 28, // C clear or Z set Unsigned lower or same.
ge = 10 << 28, // N == V Greater or equal.
lt = 11 << 28, // N != V Less than.
gt = 12 << 28, // Z clear, N == V Greater than.
le = 13 << 28, // Z set or N != V Less then or equal
al = 14 << 28, // Always.
kSpecialCondition = 15 << 28, // Special condition (refer to section A3.2.1).
kNumberOfConditions = 16,
// Aliases.
hs = cs, // C set Unsigned higher or same.
lo = cc // C clear Unsigned lower.
};
inline Condition NegateCondition(Condition cond) {
DCHECK(cond != al);
return static_cast<Condition>(cond ^ ne);
}
// Commute a condition such that {a cond b == b cond' a}.
inline Condition CommuteCondition(Condition cond) {
switch (cond) {
case lo:
return hi;
case hi:
return lo;
case hs:
return ls;
case ls:
return hs;
case lt:
return gt;
case gt:
return lt;
case ge:
return le;
case le:
return ge;
default:
return cond;
}
}
// -----------------------------------------------------------------------------
// Instructions encoding.
// Instr is merely used by the Assembler to distinguish 32bit integers
// representing instructions from usual 32 bit values.
// Instruction objects are pointers to 32bit values, and provide methods to
// access the various ISA fields.
typedef int32_t Instr;
// Opcodes for Data-processing instructions (instructions with a type 0 and 1)
// as defined in section A3.4
enum Opcode {
AND = 0 << 21, // Logical AND.
EOR = 1 << 21, // Logical Exclusive OR.
SUB = 2 << 21, // Subtract.
RSB = 3 << 21, // Reverse Subtract.
ADD = 4 << 21, // Add.
ADC = 5 << 21, // Add with Carry.
SBC = 6 << 21, // Subtract with Carry.
RSC = 7 << 21, // Reverse Subtract with Carry.
TST = 8 << 21, // Test.
TEQ = 9 << 21, // Test Equivalence.
CMP = 10 << 21, // Compare.
CMN = 11 << 21, // Compare Negated.
ORR = 12 << 21, // Logical (inclusive) OR.
MOV = 13 << 21, // Move.
BIC = 14 << 21, // Bit Clear.
MVN = 15 << 21 // Move Not.
};
// The bits for bit 7-4 for some type 0 miscellaneous instructions.
enum MiscInstructionsBits74 {
// With bits 22-21 01.
BX = 1 << 4,
BXJ = 2 << 4,
BLX = 3 << 4,
BKPT = 7 << 4,
// With bits 22-21 11.
CLZ = 1 << 4
};
// Instruction encoding bits and masks.
enum {
H = 1 << 5, // Halfword (or byte).
S6 = 1 << 6, // Signed (or unsigned).
L = 1 << 20, // Load (or store).
S = 1 << 20, // Set condition code (or leave unchanged).
W = 1 << 21, // Writeback base register (or leave unchanged).
A = 1 << 21, // Accumulate in multiply instruction (or not).
B = 1 << 22, // Unsigned byte (or word).
N = 1 << 22, // Long (or short).
U = 1 << 23, // Positive (or negative) offset/index.
P = 1 << 24, // Offset/pre-indexed addressing (or post-indexed addressing).
I = 1 << 25, // Immediate shifter operand (or not).
B4 = 1 << 4,
B5 = 1 << 5,
B6 = 1 << 6,
B7 = 1 << 7,
B8 = 1 << 8,
B9 = 1 << 9,
B12 = 1 << 12,
B16 = 1 << 16,
B18 = 1 << 18,
B19 = 1 << 19,
B20 = 1 << 20,
B21 = 1 << 21,
B22 = 1 << 22,
B23 = 1 << 23,
B24 = 1 << 24,
B25 = 1 << 25,
B26 = 1 << 26,
B27 = 1 << 27,
B28 = 1 << 28,
// Instruction bit masks.
kCondMask = 15 << 28,
kALUMask = 0x6f << 21,
kRdMask = 15 << 12, // In str instruction.
kCoprocessorMask = 15 << 8,
kOpCodeMask = 15 << 21, // In data-processing instructions.
kImm24Mask = (1 << 24) - 1,
kImm16Mask = (1 << 16) - 1,
kImm8Mask = (1 << 8) - 1,
kOff12Mask = (1 << 12) - 1,
kOff8Mask = (1 << 8) - 1
};
// -----------------------------------------------------------------------------
// Addressing modes and instruction variants.
// Condition code updating mode.
enum SBit {
SetCC = 1 << 20, // Set condition code.
LeaveCC = 0 << 20 // Leave condition code unchanged.
};
// Status register selection.
enum SRegister {
CPSR = 0 << 22,
SPSR = 1 << 22
};
// Shifter types for Data-processing operands as defined in section A5.1.2.
enum ShiftOp {
LSL = 0 << 5, // Logical shift left.
LSR = 1 << 5, // Logical shift right.
ASR = 2 << 5, // Arithmetic shift right.
ROR = 3 << 5, // Rotate right.
// RRX is encoded as ROR with shift_imm == 0.
// Use a special code to make the distinction. The RRX ShiftOp is only used
// as an argument, and will never actually be encoded. The Assembler will
// detect it and emit the correct ROR shift operand with shift_imm == 0.
RRX = -1,
kNumberOfShifts = 4
};
// Status register fields.
enum SRegisterField {
CPSR_c = CPSR | 1 << 16,
CPSR_x = CPSR | 1 << 17,
CPSR_s = CPSR | 1 << 18,
CPSR_f = CPSR | 1 << 19,
SPSR_c = SPSR | 1 << 16,
SPSR_x = SPSR | 1 << 17,
SPSR_s = SPSR | 1 << 18,
SPSR_f = SPSR | 1 << 19
};
// Status register field mask (or'ed SRegisterField enum values).
typedef uint32_t SRegisterFieldMask;
// Memory operand addressing mode.
enum AddrMode {
// Bit encoding P U W.
Offset = (8|4|0) << 21, // Offset (without writeback to base).
PreIndex = (8|4|1) << 21, // Pre-indexed addressing with writeback.
PostIndex = (0|4|0) << 21, // Post-indexed addressing with writeback.
NegOffset = (8|0|0) << 21, // Negative offset (without writeback to base).
NegPreIndex = (8|0|1) << 21, // Negative pre-indexed with writeback.
NegPostIndex = (0|0|0) << 21 // Negative post-indexed with writeback.
};
// Load/store multiple addressing mode.
enum BlockAddrMode {
// Bit encoding P U W .
da = (0|0|0) << 21, // Decrement after.
ia = (0|4|0) << 21, // Increment after.
db = (8|0|0) << 21, // Decrement before.
ib = (8|4|0) << 21, // Increment before.
da_w = (0|0|1) << 21, // Decrement after with writeback to base.
ia_w = (0|4|1) << 21, // Increment after with writeback to base.
db_w = (8|0|1) << 21, // Decrement before with writeback to base.
ib_w = (8|4|1) << 21, // Increment before with writeback to base.
// Alias modes for comparison when writeback does not matter.
da_x = (0|0|0) << 21, // Decrement after.
ia_x = (0|4|0) << 21, // Increment after.
db_x = (8|0|0) << 21, // Decrement before.
ib_x = (8|4|0) << 21, // Increment before.
kBlockAddrModeMask = (8|4|1) << 21
};
// Coprocessor load/store operand size.
enum LFlag {
Long = 1 << 22, // Long load/store coprocessor.
Short = 0 << 22 // Short load/store coprocessor.
};
// NEON data type
enum NeonDataType {
NeonS8 = 0x1, // U = 0, imm3 = 0b001
NeonS16 = 0x2, // U = 0, imm3 = 0b010
NeonS32 = 0x4, // U = 0, imm3 = 0b100
NeonU8 = 1 << 24 | 0x1, // U = 1, imm3 = 0b001
NeonU16 = 1 << 24 | 0x2, // U = 1, imm3 = 0b010
NeonU32 = 1 << 24 | 0x4, // U = 1, imm3 = 0b100
NeonDataTypeSizeMask = 0x7,
NeonDataTypeUMask = 1 << 24
};
enum NeonListType {
nlt_1 = 0x7,
nlt_2 = 0xA,
nlt_3 = 0x6,
nlt_4 = 0x2
};
enum NeonSize {
Neon8 = 0x0,
Neon16 = 0x1,
Neon32 = 0x2,
Neon64 = 0x3
};
// -----------------------------------------------------------------------------
// Supervisor Call (svc) specific support.
// Special Software Interrupt codes when used in the presence of the ARM
// simulator.
// svc (formerly swi) provides a 24bit immediate value. Use bits 22:0 for
// standard SoftwareInterrupCode. Bit 23 is reserved for the stop feature.
enum SoftwareInterruptCodes {
// transition to C code
kCallRtRedirected= 0x10,
// break point
kBreakpoint= 0x20,
// stop
kStopCode = 1 << 23
};
const uint32_t kStopCodeMask = kStopCode - 1;
const uint32_t kMaxStopCode = kStopCode - 1;
const int32_t kDefaultStopCode = -1;
// Type of VFP register. Determines register encoding.
enum VFPRegPrecision {
kSinglePrecision = 0,
kDoublePrecision = 1
};
// VFP FPSCR constants.
enum VFPConversionMode {
kFPSCRRounding = 0,
kDefaultRoundToZero = 1
};
// This mask does not include the "inexact" or "input denormal" cumulative
// exceptions flags, because we usually don't want to check for it.
const uint32_t kVFPExceptionMask = 0xf;
const uint32_t kVFPInvalidOpExceptionBit = 1 << 0;
const uint32_t kVFPOverflowExceptionBit = 1 << 2;
const uint32_t kVFPUnderflowExceptionBit = 1 << 3;
const uint32_t kVFPInexactExceptionBit = 1 << 4;
const uint32_t kVFPFlushToZeroMask = 1 << 24;
const uint32_t kVFPDefaultNaNModeControlBit = 1 << 25;
const uint32_t kVFPNConditionFlagBit = 1 << 31;
const uint32_t kVFPZConditionFlagBit = 1 << 30;
const uint32_t kVFPCConditionFlagBit = 1 << 29;
const uint32_t kVFPVConditionFlagBit = 1 << 28;
// VFP rounding modes. See ARM DDI 0406B Page A2-29.
enum VFPRoundingMode {
RN = 0 << 22, // Round to Nearest.
RP = 1 << 22, // Round towards Plus Infinity.
RM = 2 << 22, // Round towards Minus Infinity.
RZ = 3 << 22, // Round towards zero.
// Aliases.
kRoundToNearest = RN,
kRoundToPlusInf = RP,
kRoundToMinusInf = RM,
kRoundToZero = RZ
};
const uint32_t kVFPRoundingModeMask = 3 << 22;
enum CheckForInexactConversion {
kCheckForInexactConversion,
kDontCheckForInexactConversion
};
// -----------------------------------------------------------------------------
// Hints.
// Branch hints are not used on the ARM. They are defined so that they can
// appear in shared function signatures, but will be ignored in ARM
// implementations.
enum Hint { no_hint };
// Hints are not used on the arm. Negating is trivial.
inline Hint NegateHint(Hint ignored) { return no_hint; }
// -----------------------------------------------------------------------------
// Instruction abstraction.
// The class Instruction enables access to individual fields defined in the ARM
// architecture instruction set encoding as described in figure A3-1.
// Note that the Assembler uses typedef int32_t Instr.
//
// Example: Test whether the instruction at ptr does set the condition code
// bits.
//
// bool InstructionSetsConditionCodes(byte* ptr) {
// Instruction* instr = Instruction::At(ptr);
// int type = instr->TypeValue();
// return ((type == 0) || (type == 1)) && instr->HasS();
// }
//
class Instruction {
public:
enum {
kInstrSize = 4,
kInstrSizeLog2 = 2,
kPCReadOffset = 8
};
// Helper macro to define static accessors.
// We use the cast to char* trick to bypass the strict anti-aliasing rules.
#define DECLARE_STATIC_TYPED_ACCESSOR(return_type, Name) \
static inline return_type Name(Instr instr) { \
char* temp = reinterpret_cast<char*>(&instr); \
return reinterpret_cast<Instruction*>(temp)->Name(); \
}
#define DECLARE_STATIC_ACCESSOR(Name) DECLARE_STATIC_TYPED_ACCESSOR(int, Name)
// Get the raw instruction bits.
inline Instr InstructionBits() const {
return *reinterpret_cast<const Instr*>(this);
}
// Set the raw instruction bits to value.
inline void SetInstructionBits(Instr value) {
*reinterpret_cast<Instr*>(this) = value;
}
// Read one particular bit out of the instruction bits.
inline int Bit(int nr) const {
return (InstructionBits() >> nr) & 1;
}
// Read a bit field's value out of the instruction bits.
inline int Bits(int hi, int lo) const {
return (InstructionBits() >> lo) & ((2 << (hi - lo)) - 1);
}
// Read a bit field out of the instruction bits.
inline int BitField(int hi, int lo) const {
return InstructionBits() & (((2 << (hi - lo)) - 1) << lo);
}
// Static support.
// Read one particular bit out of the instruction bits.
static inline int Bit(Instr instr, int nr) {
return (instr >> nr) & 1;
}
// Read the value of a bit field out of the instruction bits.
static inline int Bits(Instr instr, int hi, int lo) {
return (instr >> lo) & ((2 << (hi - lo)) - 1);
}
// Read a bit field out of the instruction bits.
static inline int BitField(Instr instr, int hi, int lo) {
return instr & (((2 << (hi - lo)) - 1) << lo);
}
// Accessors for the different named fields used in the ARM encoding.
// The naming of these accessor corresponds to figure A3-1.
//
// Two kind of accessors are declared:
// - <Name>Field() will return the raw field, i.e. the field's bits at their
// original place in the instruction encoding.
// e.g. if instr is the 'addgt r0, r1, r2' instruction, encoded as
// 0xC0810002 ConditionField(instr) will return 0xC0000000.
// - <Name>Value() will return the field value, shifted back to bit 0.
// e.g. if instr is the 'addgt r0, r1, r2' instruction, encoded as
// 0xC0810002 ConditionField(instr) will return 0xC.
// Generally applicable fields
inline Condition ConditionValue() const {
return static_cast<Condition>(Bits(31, 28));
}
inline Condition ConditionField() const {
return static_cast<Condition>(BitField(31, 28));
}
DECLARE_STATIC_TYPED_ACCESSOR(Condition, ConditionValue);
DECLARE_STATIC_TYPED_ACCESSOR(Condition, ConditionField);
inline int TypeValue() const { return Bits(27, 25); }
inline int SpecialValue() const { return Bits(27, 23); }
inline int RnValue() const { return Bits(19, 16); }
DECLARE_STATIC_ACCESSOR(RnValue);
inline int RdValue() const { return Bits(15, 12); }
DECLARE_STATIC_ACCESSOR(RdValue);
inline int CoprocessorValue() const { return Bits(11, 8); }
// Support for VFP.
// Vn(19-16) | Vd(15-12) | Vm(3-0)
inline int VnValue() const { return Bits(19, 16); }
inline int VmValue() const { return Bits(3, 0); }
inline int VdValue() const { return Bits(15, 12); }
inline int NValue() const { return Bit(7); }
inline int MValue() const { return Bit(5); }
inline int DValue() const { return Bit(22); }
inline int RtValue() const { return Bits(15, 12); }
inline int PValue() const { return Bit(24); }
inline int UValue() const { return Bit(23); }
inline int Opc1Value() const { return (Bit(23) << 2) | Bits(21, 20); }
inline int Opc2Value() const { return Bits(19, 16); }
inline int Opc3Value() const { return Bits(7, 6); }
inline int SzValue() const { return Bit(8); }
inline int VLValue() const { return Bit(20); }
inline int VCValue() const { return Bit(8); }
inline int VAValue() const { return Bits(23, 21); }
inline int VBValue() const { return Bits(6, 5); }
inline int VFPNRegValue(VFPRegPrecision pre) {
return VFPGlueRegValue(pre, 16, 7);
}
inline int VFPMRegValue(VFPRegPrecision pre) {
return VFPGlueRegValue(pre, 0, 5);
}
inline int VFPDRegValue(VFPRegPrecision pre) {
return VFPGlueRegValue(pre, 12, 22);
}
// Fields used in Data processing instructions
inline int OpcodeValue() const {
return static_cast<Opcode>(Bits(24, 21));
}
inline Opcode OpcodeField() const {
return static_cast<Opcode>(BitField(24, 21));
}
inline int SValue() const { return Bit(20); }
// with register
inline int RmValue() const { return Bits(3, 0); }
DECLARE_STATIC_ACCESSOR(RmValue);
inline int ShiftValue() const { return static_cast<ShiftOp>(Bits(6, 5)); }
inline ShiftOp ShiftField() const {
return static_cast<ShiftOp>(BitField(6, 5));
}
inline int RegShiftValue() const { return Bit(4); }
inline int RsValue() const { return Bits(11, 8); }
inline int ShiftAmountValue() const { return Bits(11, 7); }
// with immediate
inline int RotateValue() const { return Bits(11, 8); }
inline int Immed8Value() const { return Bits(7, 0); }
inline int Immed4Value() const { return Bits(19, 16); }
inline int ImmedMovwMovtValue() const {
return Immed4Value() << 12 | Offset12Value(); }
DECLARE_STATIC_ACCESSOR(ImmedMovwMovtValue);
// Fields used in Load/Store instructions
inline int PUValue() const { return Bits(24, 23); }
inline int PUField() const { return BitField(24, 23); }
inline int BValue() const { return Bit(22); }
inline int WValue() const { return Bit(21); }
inline int LValue() const { return Bit(20); }
// with register uses same fields as Data processing instructions above
// with immediate
inline int Offset12Value() const { return Bits(11, 0); }
// multiple
inline int RlistValue() const { return Bits(15, 0); }
// extra loads and stores
inline int SignValue() const { return Bit(6); }
inline int HValue() const { return Bit(5); }
inline int ImmedHValue() const { return Bits(11, 8); }
inline int ImmedLValue() const { return Bits(3, 0); }
// Fields used in Branch instructions
inline int LinkValue() const { return Bit(24); }
inline int SImmed24Value() const { return ((InstructionBits() << 8) >> 8); }
// Fields used in Software interrupt instructions
inline SoftwareInterruptCodes SvcValue() const {
return static_cast<SoftwareInterruptCodes>(Bits(23, 0));
}
// Test for special encodings of type 0 instructions (extra loads and stores,
// as well as multiplications).
inline bool IsSpecialType0() const { return (Bit(7) == 1) && (Bit(4) == 1); }
// Test for miscellaneous instructions encodings of type 0 instructions.
inline bool IsMiscType0() const { return (Bit(24) == 1)
&& (Bit(23) == 0)
&& (Bit(20) == 0)
&& ((Bit(7) == 0)); }
// Test for a nop instruction, which falls under type 1.
inline bool IsNopType1() const { return Bits(24, 0) == 0x0120F000; }
// Test for a stop instruction.
inline bool IsStop() const {
return (TypeValue() == 7) && (Bit(24) == 1) && (SvcValue() >= kStopCode);
}
// Special accessors that test for existence of a value.
inline bool HasS() const { return SValue() == 1; }
inline bool HasB() const { return BValue() == 1; }
inline bool HasW() const { return WValue() == 1; }
inline bool HasL() const { return LValue() == 1; }
inline bool HasU() const { return UValue() == 1; }
inline bool HasSign() const { return SignValue() == 1; }
inline bool HasH() const { return HValue() == 1; }
inline bool HasLink() const { return LinkValue() == 1; }
// Decoding the double immediate in the vmov instruction.
double DoubleImmedVmov() const;
// Instructions are read of out a code stream. The only way to get a
// reference to an instruction is to convert a pointer. There is no way
// to allocate or create instances of class Instruction.
// Use the At(pc) function to create references to Instruction.
static Instruction* At(byte* pc) {
return reinterpret_cast<Instruction*>(pc);
}
private:
// Join split register codes, depending on single or double precision.
// four_bit is the position of the least-significant bit of the four
// bit specifier. one_bit is the position of the additional single bit
// specifier.
inline int VFPGlueRegValue(VFPRegPrecision pre, int four_bit, int one_bit) {
if (pre == kSinglePrecision) {
return (Bits(four_bit + 3, four_bit) << 1) | Bit(one_bit);
}
return (Bit(one_bit) << 4) | Bits(four_bit + 3, four_bit);
}
// We need to prevent the creation of instances of class Instruction.
DISALLOW_IMPLICIT_CONSTRUCTORS(Instruction);
};
// Helper functions for converting between register numbers and names.
class Registers {
public:
// Return the name of the register.
static const char* Name(int reg);
// Lookup the register number for the name provided.
static int Number(const char* name);
struct RegisterAlias {
int reg;
const char* name;
};
private:
static const char* names_[kNumRegisters];
static const RegisterAlias aliases_[];
};
// Helper functions for converting between VFP register numbers and names.
class VFPRegisters {
public:
// Return the name of the register.
static const char* Name(int reg, bool is_double);
// Lookup the register number for the name provided.
// Set flag pointed by is_double to true if register
// is double-precision.
static int Number(const char* name, bool* is_double);
private:
static const char* names_[kNumVFPRegisters];
};
} } // namespace v8::internal
#endif // V8_ARM_CONSTANTS_ARM_H_